   (when-not (describe-table client-opts table-name)
     (create-table client-opts table-name hash-keydef opts)))
 
-(defn- throughput-steps
-  "Dec by any amount, inc by <= 2x current amount, Ref. http://goo.gl/Bj9TC.
+(defn throughput-steps
+  "Implementation detail.
+
+  Dec by any amount, inc by <= 2x current amount, Ref. http://goo.gl/Bj9TC.
   x - start, x' - current, x* - goal."
   [[r w] [r* w*]]
   (let [step (fn [x* x'] (if (< x* x') x* (min x* (* 2 x'))))]

  (attr-multi-vs {:a "a1" :b ["b1" "b2" "b3"] :c #{"c1" "c2"}}) ; ''
  )

(defn- batch-request-items
  "{<table> <request> ...} -> {<table> KeysAndAttributes> ...}"
  [requests]
  (utils/name-map
   (fn [{:keys [prim-kvs attrs consistent?]}]


;;;; API - batch ops

(defn attr-multi-vs
  "Implementation detail.

  [{<attr> <v-or-vs*> ...} ...]* -> [{<attr> <v> ...} ...] (* => optional vec)"
  [attr-multi-vs-map]
  (let [;; ensure-coll (fn [x] (if (coll?* x) x [x]))
        ensure-sequential (fn [x] (if (sequential? x) x [x]))]
